A command investigation has confirmed that human error was to blame for the explosion at Hawthorne Army Depot which left seven Marines dead and eight others wounded.

"The Marines employing one of the mortars did not follow correct procedures, resulting in the detonation of a high explosive round at the mortar position," according to a press release dated May 29.

The 60 mm mortar explosion, which occurred on March 18 has resulted in three officers being relieved of command on May 8 by Brig. Gen Lukeman, the commanding general of 2nd Marine Division. The deaths and injuries occurred during a live-fire night attack aboard Hawthorne Army Depot, when a mortar round exploded in the immediate vicinity of the mortar section’s firing position.

"Lukeman relieved those officers because he lost trust and confidence in their ability to ensure proper preparation for, and conduct of, live-fire training events," according to the press release.

The officers relieved were Lt. Col. Andrew McNulty, the commanding officer of 1st Battalion, 9th Marines, Capt. Kelby Breivogel, the company commander of Company A, and Chief Warrant Officer 3 Douglas Derring, the battalion’s Marine infantry weapons officer, or Gunner, were also relieved of their duties.

The mortar section had not conducted appropriate preparatory training leading up to the live-fire event where the explosion occurred, according to the investigation which also determined that the mortar system functioned properly and found no reason to question the safety of the system, according to the press release.

No Marines or sailors have been charged with a crime or violation of the Uniform Code of Military Justice.